KiwiSDR is a software-defined radio (SDR) covering shortwave, the longwave & AM broadcast bands, various utility stations, and amateur radio transmissions, world-wide, in the spectrum from 10 kHz to 30 MHz.
Once installed it would require a relatively small amount of internet bandwidth and would be added to the available public receivers listed here:
http://sdr.hu/
The relevant kit I’m thinking of ordering:
https://www.seeedstudio.com/KiwiSDR-Kit-p-2725.html
RF wise, the space is fairly poor due to being under several rail tracks but it would be good to try a long wire out the door !
Courty
oops I hadn’t considered interference, being in an arch and all.
agreed will be interesting to see how bad it is though.
FYI: I’ve worked on a few radios LW MW in the space and the reception on most of them has been very poor.
I think this sounds intriguing, but the RF reception issue might rule it out.
Is there a way to test before you splash $300 on the kit?
I can bring my portable shortwave equipment in at some point. We can test several modes and bands in one go to see if any are usable. my gut is that the lower shortwave bands would suffer a lot of noise but we can try the higher ones and try some digital modes too.
Courty
Hi.
Honest question; what is the point – or idea behind – having a radio server the the space? What would we do with it, what would it do for us?
Lucas has a LimeSDR due to arrive in the next few weeks, so I’m sure he’d bring it in for a bit of experimentation. It does a huge range of frequencies – depending on the antenna. So could test out the arch thoroughly.
There are a few of these networks both official and amateur which are good for experiments in RF propagation and for testing transmitters. You can set up a beacon transmission and then tune from location to location testing the reception. My portable setup is 5watts but can easily get to the US in the right conditions / using the right modes so a global network is really useful for testing.
That said I still believe the arch will be too electrically noisy for a lot of modes but it could be worth a play (with both the portable and sdr setups)
Courty
Nice to see there are RF interested people here!
At home last night I made a HF loop aerial from some coax cable and tested with a rtl sdr dongle which had already been modified to support the lower frequencies. Um, so at home AM broadcast stations seemed to come in very clear, which is awesome but when tuning the SDR up to say 7 Mhz for amateur radio it was pretty much deaf. Bleh.
I may be be able to add a tuning capacitor to the loop to get it resonant there but I haven’t yet and I’m already thinking perhaps I should just get an active mini aerial instead for more bandwidth.
SDR Receiver:
Mini Whip Aerial:
How big is a proper antenna? We could mount something on the bikerack-to-be 
for SDR broadband 0-30mhz tuning, an active miniwhip is ideal because it doesn’t require tuning for it to work across the entire range. this wouldn’t be suitable for any outgoing transmission. Seems to be just around 10-20cm in length depending on variant.
for a proper amateur radio antenna as-in bi-directional communication - I have no idea what would be proper, hopefully someone skilled here could help clarify this aspect.
A proper long wire half-wave dipole for 7mhz is just under 20 meters long, even folded its 10 meters + they should be a quarter wave length up in the air (10m). The vertical antennas are normally 6+ meters so not really a starter for us.
My backpack kit has a Z-Match unit which allows you to throw a piece of wire up a tree and tune it… the wire needs to be at least 5 to 10 meters to get a good match but doesn’t care too much about being straight etc.
The bottom line is any of the whips or short wires are a compromise that will be sensitive to noise.
Courty
I blame you lot for my lack of productivity this afternoon. Currently listening to a Hungarian contest station talking to an American station via morse on 7mhz using to 2.5 meter whip pointed out the office window 
Courty
Can’t find the long wire tuner though 
awesome!!!
happy to be a bad influence for you 
I tried a whole bunch of frequencies yesterday in and around the arch and the electrical noise is very high, in most cases above the signal.
On 14mhz with a huge whip I couldn’t get anything, not even Morse. tried frequencies right up to the Aircraft bands and could only hear something when I was outside the arch in the garden area and even then it was scratchy.
I think the number of railway lines and associated equipment right above us kills most signals and seems to have a fairly wide spread too.
Will try a different antenna and try the higher frequencies next time as they tend to be less affected by the electrical noise.
Courty
On the other news, the makerspace is NSA safe from low frequency radio espionage. 
damnit
Thank you for checking it out so thoroughly Courty, what a frustrating situation indeed.
Just so folks know, technically it’s illegal to listen to stations which are not expressly public, i.e. listening to someone’s conversation encrypted or not.
